All three responded, posting videos of their #22PushupChallenge and called on other celebrities to keep the momentum going. Others, including actor/comedian Kevin Hart and Captain America starChris Evans, have answered with their own online videos.

The initiative was started as #22Pushups by the Dallas-based veterans group 22Kill. The group stated on its website that the goal was to get 22 million pushups, “to honor those who serve and to raise awareness for veteran suicide prevention through education and empowerment.”

It has been adopted by other advocacy organizations in the U.S., Canada and England. The number 22 is the daily average of U.S. combat veterans who commit suicide, according to a Department of Veterans Affairs report in 2013.